Abstract: A refrigeration machine oil composition may have good lubricating properties and sufficiently reduce friction even when a base oil containing a low-viscosity mineral oil is used and/or prevent seizure between sliding members. Such refrigeration machine oil compositions may contain a base oil containing a mineral oil, (A) at least one type selected from a specific neutral phosphate ester and an amine salt thereof, and (B) at least one type selected from a specific acidic phosphate ester, an acidic phosphite ester, and an amine salt thereof, and having a kinematic viscosity at 40° C. in a range of from 1.0 to 6.0 mm2/s.

Abstract: A lubricating oil composition which may contain a zinc dialkyl dithiophosphate, and whose color deterioration over time is alleviated. Such a lubricating oil composition may contain: a base oil (A); a zinc dialkyl dithiophosphate (B); and a sodium-based detergent (C). In such a lubricating oil composition, a content of zinc atoms may be 100 ppm by mass to 2,000 ppm by mass based on a total amount of the lubricating oil composition, and a content of sodium atoms may be 5 ppm by mass to 1,000 ppm by mass based on the total amount of the lubricating oil composition.

Abstract: A lubricating oil composition having a fluorescent compound that emits a fluorescent light. The fluorescent compound has a property of deteriorating with relevance to a deterioration of the lubricating oil composition. A deterioration measurement device having a light emitter that emits an irradiation light toward a measurement target object including a fluorescent compound, a light receiver, and a sensor. A deterioration measurement system having a lubricating oil composition and a deterioration measurement device.

Abstract: Provided are a lubricating oil degradation evaluation system and a lubricating oil degradation evaluation method capable of immediately evaluating degradation and a contamination state of a lubricating oil by including: a storage unit 10 that stores evaluation reference data 100 regarding evaluation of degradation of a lubricating oil; a creation unit 20 that acquires imaging data 210 of an evaluation lubricating oil serving as an evaluation target captured by an imaging apparatus 21 having a communication function and creates image analysis data 200 regarding degradation of the evaluation lubricating oil from the imaging data 210; and an evaluation unit 30 that creates an evaluation result 300 of a degree of degradation of the evaluation lubricating oil from the image analysis data 200 on the basis of the evaluation reference data 100.